This invention relates to a pair of corn head snapping rolls which are an integral part of each row unit in the corn head attachment of crop processing units such as combines, shellers, husking units and forage harvesters. Each such row unit utilizes a pair of counter-rotating snapping rolls mounted beneath the fore and aft extending slot of a stripper plate. In operation, the combine, with corn head in place, traverses a field so that stalks of corn enter the throat of each row unit. Each stalk entering the fore and aft extending slot of the stripper plate will be grasped between the snapping rolls. They will draw the stalk of corn downward until the ear makes contact with the stripper plate. The slot width in the stripper plate is not wide enough to allow passage of the ear, causing the snapping rolls to tear the ears free from the stalk. The loose ears are then transferred via gathering chains, augers and elevators to the crop processing unit.
U.S. Pat. No. 3,462,928 to Schreiner, etal discloses a harvester snapping roll configuration wherein the rolls are supported in cantilever fashion from the gear housing which provides driving power. Each snapping roll is relatively short and the forward end of the roll is unsupported. The rolls are fluted along their length and the effective diameter tapers from nose to the base at the gear housing end.
The U.S. Pat. No. (3,174,484) to Anderson shows a snapping roll construction composed of simple elements that are easy to assemble. The flutes on the Anderson roll structure comprise two pieces of L-shaped angle iron stock bolted to opposite faces of a square central shafting or equivalent.
Neither of the above achieve the crop processing action of our invention. With Anderson, the spacing between the tips of the flutes remains the same throughout the main body of the adjacent rolls. In Schreiner, etal there are a series of similar flutes which taper so as to overlap more near the base than at the tip end. Spacing between the flutes of adjacent rolls does not change as the rolls rotate. With our invention there are two kinds of axially extending flutes. Both are tapered so that there is more overlap at the base than at the tip of the roll. The odd numbered flutes on each roll extend radially outward from the center of the roll. The even numbered flutes, while having their roots spaced equidistant from the odd numbered adjacent flutes, extend outward at an angle which is between 20 and 30 degrees removed from the radial direction. Synchronous rotation of the adjacent rolls brings about an action which grips an interposed stalk of corn first tighter, then looser. The cyclically repeated action was found to both do a better job of snapping off ears at the butt end of the cob and keeps the corn plant intact which improves processing of stalks, leaves and weeds, thereby, significantly increasing the amount of trash removed by the snapping rolls.